The increasing of the number of the fans leads to an excessively high air speed and localized discomfort due to drafts. The radiant panels cool the area only near the wall. The analysis shows that the metal casing brings a substantial benefit due to the solar shielding it causes. A second section in which the area is completely modelled, and a third section in which a comfort evaluation is carried out. Firstly, a section in which the study area is modelled through a strong simplification that allows to represent only a slice of the domain but to immediately evaluate the role of the casing. Then, three other solutions are proposed: by increasing the number of fan coils and changing their position, by adding some radiant panels arranged on the walls, and by inserting a physical confinement as a lateral confinement. The reference configuration consists of the installation of four fan coils in the area coupled with a 3 m high metal casing used for solar shading. To improve the thermal comfort in the hall of the Angelo Hospital (Venezia) an analysis was developed by using Computation Fluid Dynamics and considering some configurations for the air-conditioning system and for the solar shading devices. In addition, a comparison with simulation with a previous version of the code, FDSv4, shows that it predicts higher temperatures and slower ascends of the smoke layer than FDSv5, the difference being lower than 12% and 100 s respectively. In order to extend the results to different designs, the model has then been applied to study a range of 16 different atrium geometries, varying the area-to-height-squared ratio from 0.4 to 3.8. This shows that the cartesian-grid simplifications proposed here are a good choice and allow for saving some computational resources. For example, at a height of 15 m, the temperature differences between all geometry approximations are lower than 10%. In general terms, good agreement between experiments and numerical simulations is found for all model roof geometries, especially far away from the fire source and the centreline.
Different cartesian-grid approximations to the real geometry of the pyramidal roof have been investigated in order to assess the effect of stair stepping on the smoke layer and the temperature field. In the present work Fire Dynamic Simulator (FDSv5) has been used to study two full-scale experiments conducted in Murcia (Spain) of 1.36 MW and 2.34 MW pool fires burning inside a 20 m cubic atrium under natural ventilation conditions.
The use of computational fluid dynamics (CFD) as a tool for the design of smoke control systems and fire protection in large spaces has become more frequent as accuracy and computational speeds increase.
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